The present invention relates to a service providing system, a virtual machine server, a service providing method and a program thereof. More particularly, it relates to a service providing system, a virtual machine server, a service providing method and a program thereof capable of efficiently operating a virtual machine in accordance with services to be delivered.
In related technology, with a development of high performance PC (personal computer) server machines, virtual machine systems have been developed in which virtual machines virtualize computers.
The virtual machine systems are platforms which operate on physical machines, and cause plural virtual machines to operate.
Virtual machines have, for a long time, been implemented on large-scale computers and their main objective is to effectively take advantage of computer resources through computer-resource intensive utilization. In this case, instead of using plural computers, a virtual machine system is operated on one computer in such a manner that plural virtual computers can be run on the virtual machine system.
A virtual machine system installed on a PC sever is often employed for the purpose of computer-resource intensive utilization. In addition, recently in the virtual machine systems installed on PC servers, a virtual machine migration system has been developed. In the virtual machine migration system, a virtual machine on the virtual machine system is transferred onto another virtual machine system while the virtual machine keeps running intact. This kind of the virtual machine migration is developed for the purpose of optimizing computer resources etc.
Virtual machine migration is useful for increasing the flexibility of service environments. For example, if it becomes necessary to take security into consideration while a service is provided, a virtual machine which is providing the service can be migrated to a more secure location.
For example, Japanese Unexamined Patent Application Publication No. 2009-265894, Japanese Unexamined Patent Application Publication No. Hei05(1993)-088922 and Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2007-506169 disclose these related technologies.
On the other hand, in virtual machine migration, it is necessary for a client, which is using the virtual machine, to continuously be provided with the same service as the client is provided before the migration. This inhibits increasing the flexibility of virtual machine migration.
For example, there is a problem in the related technologies, in that if one of a plurality clients which is provided with a service can not access the virtual machine after the virtual machine is migrated to a secure location, such a migration should be not executed because the service should be provided to the plurality of clients continuously before and after the migration of the virtual machine. That is to say, in this situation, it is impossible to migrate the virtual machine to a secure location if one of the plurality of clients can not access the virtual machine.